1. Field of the Invention
This invention relates to an automobile air conditioning system which supplies air to both the front and rear sections of the passenger compartment.
2. Description of the Prior Art
There are currently known a number of air conditioning systems for automobiles, which supply air to both the front and rear sections of the passenger compartment of an automobile.
These air conditioning systems comprise an evaporator for cooling the air that enters via the air inlet port and a heater core which is located behind the evaporator. An air mixing damper is located in front of the heater core, and opens and closes to regulate the amount of air flowing through the heater core, so that the temperature of air flowing to the passenger compartment is controlled.
With this type of air conditioning system, a single mode can be selected so that the conditioned air is blown out only via a front vent unit. When a dual mode is selected, the air is sent to both the front and rear vent units.
There is another type of air conditioning system, which allows part of the air cooled by the evaporator to pass through to the front vent unit, bypassing the heater core, thereby increasing the amount of airflow through the front vent unit and enabling the noise level to be reduced.
However if the bypass remains open when the single mode is switched to the dual mode during a maximum cooling mode, the amount of airflow through the front and rear vent units may be uneven, making it difficult to aircondition the compartment evenly.